1. Field of the Invention
This invention relates to a system and method for improving the visibility of objects within a visual field and in particular to a system and method for use in an automotive vehicle under adverse optical conditions.
2. Description of the Prior Art
Generally, safety requires that the driver of an automotive vehicle be protected from being dazzled by the headlights cast by an automotive vehicle in the opposite lane.
Japanese published unexamined patent application No. 52-101526 discloses a prior art system for shutting out the headlights cast by an automotive vehicle in the opposite lane. This system employs a pair of polarizing filters. One filter can pass only the horizontally- or vertically-vibrating component of the headlight beam and is placed in front of the headlights of an automotive vehicle. The other filter can conversely pass only the vertically- or horizontally-vibrating component of the headlight beam and is placed on the windshield of the automotive vehicle. However, this system is less effective in cases where the vehicle in the opposite land lacks the same polarizing filters as are used on one's own vehicle.
Japanese published unexamined patent application No. 49-72830 or 50-138526 also discloses a system for suppressing transmission of headlights cast by an automotive vehicle in the opposite lane through a vehicular windshield by means of a liquid crystal panel and an electronic circuit for controlling the transmissivity of the liquid crystal panel. However, since this system darkens the entire forward visual field of the vehicle on which the headlights are incident, at the moment the liquid crystal filter transmissivity is reduced the driver of the filtering vehicle may fail to recognize irregularities, obstacles and/or pedestrians crossing or standing in the road within the forward visual field.